The stakes in the 5-day-old San Francisco Symphony strike got a lot higher on Sunday, as the orchestra canceled its upcoming East Coast tour with musicians and management still far apart on salaries and benefits.

Representatives of the musicians union and management had been meeting all week with a federal negotiator in an effort to resolve the dispute, including several late-night marathon sessions in recent days. But on Sunday afternoon, just two days before the orchestra was scheduled to leave, there was still no prospect of an agreement.

Executive Director Brent Assink said that the mediator had proposed a "cooling-off period" that would have allowed the tour to go forward while the talks continued. But he said the musicians had rejected that idea.

"We are deeply disappointed that the musicians are continuing to reject proposals for a new agreement," he said in a statement. "We have negotiated in good faith since September, have shared volumes of financial information, and have offered many different proposals that we had hoped would lead to a new agreement by this time. We will continue to work hard to resolve this situation."

Violist David Gaudry, the chairman of the musicians' negotiating committee, was not immediately available for comment. Last week, he told The Chronicle that the musicians had made it "abundantly clear" that they would not leave San Francisco for the East Coast without a contract.

Musicians walked off the job on Wednesday, leading to cancellations of four scheduled performances of Mahler's Ninth Symphony in Davies Symphony Hall. That work, along with music by Brahms and Samuel Carl Adams, was to form the centerpiece of the four-concert tour, with scheduled performances in New York's Carnegie Hall, the New Jersey Performing Arts Center in Newark and the Kennedy Center in Washington, D.C.

The cancellation will represent a financial blow for the orchestra, as well as a potential embarrassment on the public stage. The last strike by Symphony musicians, in 1996-97, was a bitter nine-week affair that led to the cancellation of 43 concerts.